From: valis sec@valis.email
[ Upstream commit 76e42ae831991c828cffa8c37736ebfb831ad5ec ]
When fw_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter.
This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.
Fix this by no longer copying the tcf_result struct from the old filter.
Fixes: e35a8ee5993b ("net: sched: fw use RCU") Reported-by: valis sec@valis.email Reported-by: Bing-Jhong Billy Jheng billy@starlabs.sg Signed-off-by: valis sec@valis.email Signed-off-by: Jamal Hadi Salim jhs@mojatatu.com Reviewed-by: Victor Nogueira victor@mojatatu.com Reviewed-by: Pedro Tammela pctammela@mojatatu.com Reviewed-by: M A Ramdhan ramdhan@starlabs.sg Link: https://lore.kernel.org/r/20230729123202.72406-3-jhs@mojatatu.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/sched/cls_fw.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c index 41f0898a5a565..08c41f1976c47 100644 --- a/net/sched/cls_fw.c +++ b/net/sched/cls_fw.c @@ -266,7 +266,6 @@ static int fw_change(struct net *net, struct sk_buff *in_skb, return -ENOBUFS;
fnew->id = f->id; - fnew->res = f->res; fnew->ifindex = f->ifindex; fnew->tp = f->tp;